Many PSMA-binding monoclonal antibodies are known. For instance, 7E11, which has been approved by the FDA for the study of metastases expressing PSMA, is a monoclonal antibody that binds the intracellular portion of PSMA. Unfortunately, however, 7E11 does not bind viable cells, but only necrotic or apoptotic cells within a tumour mass.
Monoclonal antibodies such as J591, J415, J533 and E99 have subsequently been produced. These antibodies recognise epitopes on the extracellular domain of PSMA and therefore bind viable cells.
J591 has in particular been used for several in vitro studies and in animal models both diagnostically and therapeutically and is still under clinical experimental study.
Finally, EP1726650 discloses another monoclonal antibody and an scFv fragment thereof which binds to PSMA.
Hereinafter, the term “fragment of the antibody binding the antigen” indicates one or more fragments of this antibody which maintains/maintain the ability to specifically bind PSMA.